Toward a prostate specific antigen-based prostate cancer diagnostic assay: preparation of keyhole limpet hemocyanin-conjugated normal and transformed prostate specific antigen fragments.

Prostate specific antigen (PSA) molecules secreted by cancerous and normal prostate cells differ in their N-linked glycan composition, while the peptide backbone appears to be conserved. Antibodies selectively recognizing such differentially glycosylated PSA structures could form a basis for a new diagnostic assay for prostate cancer. Twenty-amino acid PSA fragments carrying di-, tri-, and tetrabranched complex-type glycans were prepared by total synthesis and conjugated to maleimide-modified keyhole limpet hemocyanin (KLH) carrier protein through backbone Cys residues. These glycopeptide/KLH conjugates were then used for antibody generation.

Small molecule protein-protein inhibitors for the p53-MDM2 interaction.

This article describes recent progress in the development of small molecule protein-protein inhibitors of the p53-MDM2 (purine double minute 2, or HDM2 for the human congener) protein-protein interaction, with special attention to the diversity of chemotypes reported to disrupt this protein-protein interaction. In >50% of all human cancers, the tumor suppressor 53 KDa phospho-protein p53 is either mutated or deleted. The discovery that MDM2 (HDM2) negatively regulates p53 and therefore inhibits the tumor-suppressor activity of p53 has instigated numerous drug discovery campaigns aimed at disrupting this protein-protein interaction as a potential cancer therapy. Once regarded as intractable targets disrupted by only large macromolecules, protein-protein interactions (PPI) are now mainstream targets due in large part to the intensive effort applied to the study of p53 and the surprising diversity of small molecules (peptides, natural products, terphenyl and other alpha-helix mimetics, chalcones, piperidines, piperazines, fused indoles, isoindolinones, spiro-oxindoles, cis-imidazolines (nutlins), quinolinol and benzodiazepines) capable of disrupting the p53-HDM2 PPI. In addition, drug discovery researchers have employed a number of screening approaches and technologies to identify SMPPIs of the p53-HDM2 interaction, and these discovery paradigms will be discussed. This review will detail the biology of the p53-MDM2 interaction, the major classes of SMPPIs and key medicinal chemistry and in vitro/in vivo biological data reported through October 2006.